Up to now, there have been proposed various techniques, such as that for uniformly mixing a raw material gas and a reactive gas and that for uniformly injecting gases onto a wafer, as means for improving the in-plane uniformity in the distribution of, for instance, thickness, quality, and composition or the like of a film in a wafer when a thin-film is produced by a CVD method, for instance, an MOCVD (Metal Organic Chemical Vapor Deposition) method.
For example, Patent Document 1 discloses a thin-film manufacturing apparatus for producing a thin-film by an MOCVD method, in which film formation is performed by introducing a gas mixture composed of a vaporized raw material gas and a reactive gas into a film-forming chamber with a vacuum atmosphere, and inducing a vapor phase chemical reaction on a substrate to be treated, such as a wafer, which is placed on a stage disposed within the film-forming chamber. The thin-film manufacturing apparatus is configured such that a shower head opposed to the stage is arranged on the upper portion of the film-forming chamber to enable the gas mixture to be uniformly sprayed onto the substrate through the shower head.
FIG. 10 shows a configuration example of a shower head 1. The shower head 1 is composed of a metal head body 2 provided with a introduction pipe 2a through which a gas mixture composed of a raw material gas and a reactive gas is introduced, and a metal shower plate 3 which covers an opening portion of the head body 2. The shower plate 3 is provided with a plurality of minute shower holes 3a through which the gas mixture passes. A space 4 for distributing the introduced gas mixture across the entire region in which the shower holes 3a are formed is provided between the head body 2 and the shower plate 3.    Patent Document 1: JP 2004-35971 A    Patent Document 2: JP 11-54459 A